This project is focused at understanding the basic control mechanisms responsible for expression of the human interleukin 2 (IL-2) gene. Particular items within this study include (1) expression of the human IL-2 gene in mouse fibroblasts with DNA-mediated transfer; (2) mechanism for the activation of IL-2 expression in MLA 144 cells by a retrovirus insertion in the gene; and (3) role of 3' sequences in controlling IL-2 expression.